268 



CARNEGIE INSTITUTION OF WASHINGTON. 



with the 60-inch. The 100-inch telescope has been used ahnost ex- 

 clusively for faint stars and for a few selected objects south of —30° 

 declination which are beyond the reach of the 60-inch reflector. 

 The observing list for the latter instrument consists to a large extent 

 of stars for which determinations of absolute magnitude are being 

 made and includes stars with a wide range in apparent brightness. 

 The following table shows the number of stars of the various magni- 

 tudes observed with the two reflectors at the Cassegrain focus: 



Radial Velocities. 



The principal results obtained during the year are as follows: 



(1) The radial velocities of 253 stars in addition to those of types 

 Md and R have been determined from three or more spectrograms, and 

 these stars have been transferred to the list of objects with constant 

 velocities. 



(2) About 20 spectroscopic binaries have been discovered, for several 

 of which the orbits are now under investigation. 



(3) The elements of the orbits of 7 spectroscopic binaries have been 

 computed and published by Mr. Sanford. These include the com- 

 panion of a Herculis with a period of 51.6 days, and two dwarf stars 

 of type K, Lalande 29330 and Lalande 46867, the latter of which has 

 bright H and K lines. Preliminary elements of three other binaries. 

 Boss 2227, Boss 2447, and A. Oe 12584, have been derived. Four of 

 these ten binaries show the lines of both components. The large ve- 

 locities of the center of mass of Lalande 29330 and A. Oe 12584 are 

 noteworthy, amounting to —60 and — 98± km. per sec. respectively 



(4) The Cepheid variable X Cygni has been investigated by Mr. 

 Duncan, and the elements of its orbit have been determined on the 

 assumption that this type of variable is actually binary in character. 



(5) The variable star S Antlise, usually classed as a Cepheid variable, 

 has proved to be of the Algol type and shows two spectra. The orbit 

 has been calculated by Mr. Joy, and the results will be published soon. 



(6) Observations of the cluster-type variables RS Bootis, XZ 

 Cygni, and RV Ursse Ma j oris indicate a somewhat larger range of 

 velocity for these stars than for the normal Cepheid variables. The 

 'Velocity of the system" in the case of ten cluster- type variables has 

 been found to have values ranging from +70 to —180 km. but no 

 relationship with distance from the Galaxy is apparent. 



